The HNRC has expanded its international focus in recognition of opportunities for incremental knowldge of the neuropathology of HIV that can be addressed uniquely in resource-limited settings (RLS). The pertinent scientific topics include effects of viral and host genetic and mitochondrial factors;availability, efficacy, and timing of antiviral treatments;region-specific cofactors (e.g., exposure to co-infecting pathogens, specific drugs of abuse, trauma);and how sociocultural and environment differences affect the epidemiology, phenomenology, pathogenesis, and effectiveness of treatment for of neuroAIDS. Methodological issues include development of valid assessments of neurocognitive and daily functioning for use in diverse linguistic and cultural settings and in illiterate or semiliterate persons, as well as adaptation of neuromedical ascertainment methods for successful deployment in RLS. The International Core proposes to identify opportunities for international research and to facilitate partnering between HNRC investigators and scientist-clinicians in RLS in order to build capacity to undertake neuroAIDS research that is in line with HNRC scientific themes, and that is responsive to the needs and circumstances of those settings. The Core has coordinated scientific consultation, mentoring, training, and technical assistance designed to develop collaborative, investigator-initiated, fundable international research programs on NeuroAIDS. We have secured an NIH U-13 grant for 3 international NeuroAIDs training meetings and created the International Consortium of NeuroAIDS Scientists to maintain contact among investigators between meetings. During the last funding period, the International Core supported (1) baseline and multiple follow-up evaluations for an R- 01 study of HIV neurocognitive complications in two risk groups in China, (2) an R-21 study of perinatally infected Romanian adolescents, (3) an R21 study of NeuroAIDS in Brazil, (4) an R01 study of neurocognitive impairment after antiviral treatment initiation in Pune, India, and (5) an R01 study of effects of viral clade on neuroAIDS in four of the above sites and the US, as well as a number of smaller developmental projects. The International Core website consolidates information and facilitates access to resources. Our programs of on-site training and developmental grants for international colleagues (in coordination with Developmental Core) have promoted multiple developmental studies, and our communications and data management capacity has assisted investigators at several collaborating international sites.